Steam-boiler.



No. 754,348 PATENTED MAR. 8, 1904.

F. J. ROWAN.

STEAM BOILER.

APPLICATION FILED D50. 19, 1903.

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' mun/70R By lit/um 1mm No. 754,348. PATENTED' MAR. 8, 1904.

P. J. ROWAN.

STEAM BOILER. 7 APPLICATION FILED DEC. 19, 1903.

N0 MODEL.

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STEAM BOILER. APPLICATION FILED DEC. 19, 1903/ 5 SHEETS-SHEET a.

N0 MODEL.

F. J. ROWAN. STEAM BOILER.

APPLICATION FILED DEG. 19 1903 N0 MODEL.

PATENTED MAR. 8, 1904.

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- No. 754,348. PATENTED 8, 1904.

F. 1T. ROWAN. STEAM BOILER.-

APPLIOATION FILED DBO. 19, 1903. m) MODEL. 5 s.m-r.s-asm*r 5.

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UNITED STATES.

Patented March 8,1904.

PATENT OFFICE.

' FREDERICK JNO. ROWAN, or GLASGOW, SCOTLAND.

' STEAM-BOILER,

SJPECIFZLGATION forming part of Letters Patent No. 754,348 dated March8, 1904. Application filed December 19,1903. SeiialNo-185,846. (Nomodel.)

To all whom it may concern} Be it known that I, FREDERICK JOHN RowAN,engineer, a subject of the King ofGreatBritain and Ireland,and aresident of Glasgow, Scotland, have invented certain new and usefulImprovements in Steam-Boilers, (for which an application for a patenthas been filed'in Great Britain, No. 3,328, bearing date the 12th 7 ofFebruary, 1903,) of which the following is a specification.

My invention has for its object the rendering of the heating-surface ofboilers and feedheaters more efficient as regards the transmission ofheat. I

It is well known that the amount of heat hitherto transmitted from thefuel to the water in boilers per unit of their heating-surface bearsonly an 'extremelysmall proportion to that which that surface is capableof transmitting. It is also known that results obtained in evaporatorsshow from fourteen to fifty times the rates of evaporation per 'unitobtained in boilers,so that the room for improvement in the latter ismanifest. Experiments on heat transmission have also shown that anevaporation of from fifty to eighty pounds of water per square foot ofsurface per hour is possible in boilers without undue heating of themetal, and on this account I have devised improvements with a view toobtaining at any rate a portion of that increased rate of evaporation inboilers.

In carrying my improvements into practice I use means to divide both thewater and the hot gases into a number of more or less minute streamssomewhat after the fashion of the film system used-in multiple-effectevaporators. I also employ means to increase the length of travel ofboth water and gases over the heating surface, thus prolonging theirtime of contact with the surface while being able to increase theirvelocity of movement over it without increasing the total amount'ofsurface in a given boiler. I also make use as far as possible ofthe.countercu rrent system in directing the course of movement of' waterand hot gases, and preferably employ means for carrying on thecombustion of the fuel under a considerable increase of atmosphericpressure. My improvements may,how

takenon'the line 2 2 of Fig. 1.

ever, be combined with ordinary gratecom- V bustion with either forcedor natural draft, although that system is the cause of a great loss ofheat.

My improvements are applicable to watertube boilers with eithervertical, verticallyinclined, horizontal, or horizontally-inclined tubesor with hanging tubes of the Perkins? or Field pattern with concentricinner tube.

In order that my said invention and the manner of carrying same intopractice may be properly understood, I have hereunto appended fivesheets of explanatory drawings, in which 4 Figure 1 is a sectionalelevation ofa combined steam boiler and feed-water heater as constructedin accordance with my improvements, and Fig. 2lis a horizontal sectionas Fig. 3 is a view corresponding to Fig. 1, but showing the hot gasesor products of combustion and the feed-water flowing or passing in theopposite direction to showing the boiler-tubes as fitted withcurrent-directing shields. Fig. 1 is a sectional elevation of asteam-generator, which maybe used in connection with gas-engines. Fig. 5is a detached sectional elevation of one of the tubes shown in Fig. 1 asfitted with liquid- .directing spiral inside and spiral passage for theheating-gases outside. Fig. 6 is a similar view illustrating the shieldor film form of liquid circulation; section of same, while Fig. 8 is amodified form 'offilm-directing spiral; and Fig. 9 is a sectional view'of theNiclausse type of tubes fitted with ribbon spirals.

Referring to Figs. 1 and 2 of the drawings, I construct, for example, aboiler of vertical water-tubes connected at top and bottom ends toheaders or boxes 1 and 2, respectively, of

rectangular or other section coupled together in such a way as to insurea free and equal supply of feed-water to all the tubes below and freeaccess at the top forthe escape of the steam to the steam drum orcollector 3. Inside of each of these watertubes 4. is placed a spiral,such as'a' ribbon spiral 5, of thin sheet-steel or any other suitablemetal, and

each tube 4, or it may be a group of tubes, is

that shown in Fig. 1, and

and Fig. 7 is a horizontal internal tube surrounded by a larger tube 6,which may be lined with fire-brick .or other refractory sub stance,forming a spiral flue or passage 7 for the hot gases round the tube ortubes at in the direction opposite to that taken by the, water in theinternal spiral 5. The spiral may be formed of fire-brick of hexagonalor other shape in plan and the outer tube 6 may be dispensed' with. Insome cases the outer annular tube 6 may form the water-circulating spaceand the heating-gases pass through the inner tube}, in which case theouter tubes would be made of metal and be fitted with metal'spirals andthe connections be arranged accordingly. I prefer, as shown in Fig. 1,to cause the water to ascend in the boiler-tubes 4, while, the flame andhot gases descend through the annular tubes 6. In this Way the hottestwater meets the hottest gases at the top of the tubes and steam isproduced in such a way as to insure that the minimum of water is carriedup by it into the steam-space 3. In the case of this design afeed-heater of similar construction is placed at the back of the boiler,as shown in Fig. 1, or in any convenient position, so that the .wastegases from the boiler may pass through the fluespirals in it, while thefeed-water from the pipe 8 passes into the header 9 of feed-heater, andis caused to flow in the opposite direc tion, passing down through thetubes 4 in heater to the header 2 at through the tubes 4 of boiler tothe upper header 1.

Instead of the ribbon spiral in the interior of the water-tube 4; I can,as shown in Fig. 3 and in detail in Figs. 6 and 7, makeuse of an 10 ofsmaller diameter, having rings or pieces 11 projecting from it to thewater-tube at an angle downward, so as to direct the waterin a thinstream or film over the inner surface of the water-tube 4. A

conical nozzle or distributer 12, Fig. 6, at the partment while inflowend first spreads the water over the tube-surface, and the inner tube 10with proections 11 continues the process. Underneath to escape into theinner tube 10, which is prolonged by the nozzle 12 into the steam-space14 of the header 1. The top headers 1 in this case are separated intotwo compartments by a diaphragm 15-, fixed or movable, the water beingcontinuously fed into the lower comthe steam escapes into the highercompartment 14. The water-tubes 4:

are surrounded by spiral-shaped flues or passages as in the formerdesign shown in Figs. 1 and 2, but the course of the gases around theboiler-tubes 4 will be upwardas the water flows downward. The feed-waterheater may be arranged on a similar plan. The water is pumpedinto thelower header 9, and'is forced by thepressurefrom a circulating-pump upthe tubes 4, fitted with spirals 5 -in the feed-heater, and" afterpassing into bottom'and then up 17 with small Fig. 3,

of outer tube same may be fitted, as in Fig.

8, with a top part 12 extending down from steam-space compartment 14 ofheader 1 and have an outer surface of volute or spiral indentations 16formedpn the part 12 at or below where the water enters the tubes 4, soas to give a spiral or spinning action to the column of water passingdown the tube 4, while the steam generated will pass up through thecenter of this water column and escape by the hollow top 12 into thesteam space let of header 1, to water-tubes placed horizontally orotherwise without serious mechanical difiiculty. In such a case thewater would not fall by gravity and would be caused to flow in theboiler by 'an ordinary circulating-pump in order to give it sufiicientvelocity for successful heat transmission. I may however, also use thecirculating-pump'with vertical tubeboilers to increase the speed ofwater circulation.

In the case of Perkins or Field tubes with concentric inner tube,as-shown in Fig. 9, I cause the water to be forced in by. the inner tube4., and by placing a ribbon spiral 5 in the space between it and theouter tube 6 I cause the water to get animproved circulation, and

the inner tube 4 will also be maintained in position centrally.

I use preferably an external firing-chamber grate 18 and considerabledepth of fuel, air under pressure being delivered both below the grateand over the surface of the fire. The coal can be fed automatically andany desired pressure maintained in the firing-chamber and boiler-fluesby havingan air-lock for the coal-hopper 19 and making theboiler-casings pressure-proof. Theordi: nary inside grate does notreadily lend itself to high-pressure combustion. I combine airheatersfor extracting waste heat from the hot gases and transferring it to theair wanted for These arrangements are applicable combustion and myarrangement of boiler and feed heater enables me to have on'ly theair-heater in the form of tubes 20' in the uptake 21 leading to thechimney.

The'same construction of'feed-heaters may be employed where steaminstead of waste furnace-gases is used as the heating medium.

In this case the steam may be passed in either direction in either theouter or the inner tube, the water being in the remaining one;

In the arrangement shown in Fig. 4 the air.

paratus comprises a steam generator which would be very suitable, foruse 1 z 5 in connection withgas-producing and utilizing plant, so I Ithat theexhaust-gases from the gas-engines can be utilized to generatesteam for in ecting into the gas-producers. In this arrangement thewater is fed to the heater 9, from whence it passes down the tubes4,.fitted with spirals 5, to the bottom header 2 and then ascendsthrough the tubes 4. to the top header 1 and the generated steam,.passesto the drum 3, while the exhaust-gases from the gas-engines would passin the opposite direction from the inlet branch 22 downward through theone set of outer spiral tubes 6 and then upward the other set to theoutlet 23 and so heat the central water-tubes 4 and generate the steam.

Having now described my invention, What I claim as new, and desire tosecure by Letters Patent, is

1. In steam-boilers and in feed-heaters the combination comprisingwater-tubes,'. means within the water-tubes for dividing theflowdividing the flowing water into minute streams in combination withan outer equivalently formed or fitted tube or passage through which theheating gases or steam pass in the oppo site direction substantially asherein described.

3. In combination a steam-boiler, a feedheater, water-tubes, meanswithin the watertubes for dividingthe flowing water into minute streamsand an outer equivalently formed or fitted tube or passage through whichthe heating gases or steam pass in the opposite direction substantiallyas herein described.

4. In steam-boilers and infeed-heaters, the combination comprisingwater-tubes fitted with film-tubes, heating-tubes fitted with spirals,and top and bottom headers, the top header being fitted with ahorizontal dividing: plate, and film-tubes carried above said plate,substantially as herein described.

In testimony whereof I have signed my name to this specification in thepresence of two subscribing witnesses.

FRED. JNO. ROWAN.

Witnesses:

JOHN SIME, R. O. HOWSON.

